Not applicable.
Not applicable.
1. Field of the Invention.
The present invention relates, generally, to testing apparatus and methods within the telephony industry. More particularly, the invention relates to telephone test set equipment, and has particular utility as an apparatus and method for preventing the unintentional disruption of high-speed data traffic on telecommunication lines, for integrating field service test equipment into one test set, and for providing audible line condition announcements.
2. Background Information.
The state of the art in general includes various apparatus and methods for monitoring telecommunication lines to detect communication signals. One such apparatus is a conventional test set which has a high impedance monitor mode that allows eavesdropping on telecommunication lines and an Off-Hook mode that may disrupt an existing signal on the line. If the spectrum of the signal falls into the voice band of communication (300 Hz to 3.3 kHz), the technician will hear the signal on the line when the test set is in the monitor mode and will know that the mode of the test set should not be changed from monitor to Off-Hook. However, many data lines, including T1, Eb 1, DSL and ISDN lines, have spectral energy that falls outside of the voice band of communication and thus is beyond the normal frequency range of hearing for humans. Since the ultrasonic information on these data lines cannot be heard, there is a substantial risk that an operator may incorrectly conclude that a signal is not present and place the test set from monitor to Off-Hook. When the test set is placed in the Off-Hook mode, the AC and DC impedance of the test set drops to levels which will adversely effect the data integrity of most data lines.
The state of the art includes various devices and methods for detecting data traffic on a phone line. The known art includes frequency meters that monitor the line for the presence of signals. These frequency meters may include analog discriminators for prescribed frequency bands, and LEDs that provide a visual indication of the frequency bands present in any detected signal. The state of the art also includes various volt and current meters.
This technology is believed to have significant limitations and shortcomings. One problem is that this technology is not adapted for handling DSL loops; i.e. loops that have both a POTS (Plain Old Telephone Service) signal in the voice band frequency range of 300 Hz to 3 kHz, and an ultrasonic ADSL (Asymmetric Digital Subscriber Line) signal in the frequency range of 12 kHz to 1.1 MHz. In this situation, even though ADSL signals are detected, it is still desirable to bring the test set off hook to draw a dial tone in the voice band. However, doing so with the known technology is detrimental to the ADSL signals. Another problem with the known technology is that it requires a non-trivial amount of training for a technician to properly identify the status of the line being tested.
This invention provides an apparatus and method for preventing the unintentional disruption of high speed data traffic on telecommunication lines including DSL lines, for integrating field service test equipment into one user-friendly test set, and for providing audible line condition announcements which is believed to constitute an improvement over existing technology.
The present invention provides a data protector for telephony test equipment that generally comprises a relay for selectively connecting the telephony test equipment to a telecommunication line, and electronic circuitry. The electronic circuitry includes a detector portion adapted for detecting signals within a continuous band of frequencies present on the telecommunication line, and a microcontroller. The microcontroller has a frequency counter function for determining whether data is present on the telecommunication line, a relay connect control function for selectively controlling the relay to connect the telephony test equipment to the telecommunication line, and an alert operator function for producing a signal if the detected frequency is above a predetermined threshold.
The data protector is preferably a ADSL-compatible data protector with line condition announce, wherein a ADSL filter is connected between the telephony test equipment and the telecommunication line. The ADSL filter is adapted for preventing the telephony test equipment from detrimentally affecting DSL frequencies while enabling POTS frequencies to pass through to the telephony test equipment. The electronic circuitry for an ADSL-compatible data protector further includes a ADSL compatible voltage protection portion electrically connected between the telecommunication line and the detector portion. The ADSL compatible voltage protection portion is adapted for protecting against large voltage spikes and further is adapted for minimizing signal distortion that may introduce harmonic frequencies that may interfere with signals in higher frequency bands.
The data protector with voice announce further includes a voice production portion operably connected to the microcontroller. The alert operator function produces an alert signal received by the voice production portion. In response to receiving the alert signal, the voice production portion produces a corresponding voice announcement signal to a receiver in the telephony test equipment.
The present invention further provides a method for preventing telephony test equipment from unintentionally disrupting signals on telecommunication lines that generally comprises the steps of: providing a relay between the telecommunication test equipment and the telecommunication line; providing electronic circuitry including a single band frequency counter; determining whether data signals are present on the telecommunication line using the single band frequency counter; in response to determining that data signals are not present on the line, closing the relay to connect the telecommunication test equipment to the telecommunication line; and in response to determining that data signals are present on the line, providing an indication to the technician that data is present and preventing connection between the telecommunication test equipment and the telecommunication line.
The data protector of the present invention either may be incorporated into or used as an add-on in conjunction with telephony test equipment, such as a test set for example, to avoid disruption of high speed data traffic on telecommunication lines. The data protector maintains a disconnect between the test set and the line until it can be verified that telecommunication signals are not present on the line. The data protector has two modes of operation. In the first mode, DC voltage is detected causing the device to power up automatically and to automatically check for the presence of data, i.e. a signal with a frequency outside the normal voice band. If no data is found, a connection to the line is made automatically allowing the operator to place the test set Off-Hook. If data is found, a connection to the line will not be made unless the operator consciously chooses to override the lockout or disconnect. This may be desirable to draw a dial tone in the voice band of a DSL loop, for example. In the second mode, DC voltage is not detected. A user actuates a test button (TEST switch S1) to power up the device and check for the presence of data. If no data is found, a connection to the line is made allowing an operator to place the test set Off-Hook.
The data protector utilizes a wide band RF amplifier and is controlled by a microprocessor/microcontroller. Together, the wide band RF amplifier and the microcontroller form a single or continuous band digital frequency detector. The microcontroller counts the signal cycles to detect the frequency. An audio output signal, i.e. the voice announce signal, is transmitted to the test set upon detection of any data signals outside of the normal voice band. The voice announce signal indicates to the operator of the test set that data is present and that a connection to the line will not be made if the operator attempts to place the test set Off-Hook. The voice announce signal is produced by a voice production portion of the circuitry, which includes a voice generator and an audio amplifier, and which is controlled by the microcontroller. Therefore, the data protector has a line status announce feature (i.e. an English voice signal) that actually tells the technician whether data is present, and because of the inclusion of the voltage and current sensor portions, the line voltage and loop current of the line under test. This voice announcement signal is heard in the receiver of the test set.
The features, benefits and objects of this invention will become clear to those skilled in the art by reference to the following description, claims and drawings.